#include <bits/stdc++.h>
using namespace std;

int main() {
    string s = "Hello World Hello";
    
    size_t pos = s.find('o');
    cout << pos << endl;
    
    size_t subpos = s.find("Hello", 6);
    cout << subpos << endl;
    
    if (s.find("Python") == npos) 
        cout << "未找到" << endl;
    
    string substr = s.substr(6, 5);
    cout << substr << endl;
    
    return 0;
}
